Incidence of colorectal cancer in BRCA1 and BRCA2 mutation carriers: results from a follow-up study.

BACKGROUND: The BRCA1 and BRCA2 genes confer increased susceptibility to breast and ovarian cancer and to a spectrum of other cancers. There is controversy regarding the risk of colorectal cancer conferred by germline mutations in these two genes. METHODS: We followed 7015 women with a BRCA mutation for new cases of colorectal cancer. Incidence rates in carriers were compared with population-specific incidence rates, and standardised incidence ratios (SIRs) were estimated. The expected numbers of cancers were computed by multiplying person-years at risk by the appropriate age-, sex- and country-specific incidence rates from the five countries. RESULTS: Twenty-one incident colorectal cancer cases were observed among all mutation carriers, compared with 23.6 cases expected. The SIR for BRCA1 carriers was 0.92 (95% confidence interval (CI), 0.54-1.40, P=0.7) and for BRCA2 carriers was 0.82 (95% CI, 0.30-1.81, P=0.7). The SIR for colon cancer was 3.81 (95% CI 1.77-7.23) for women below the age of 50 years (both genes combined) and was 0.60 (95% CI 0.33-1.00) for women aged 50 years and above. CONCLUSION: The risk of colorectal cancer is increased in female carriers of BRCA1 mutations below the age of 50 years but not in women with BRCA2 mutations or in older women.

The incidence of pancreatic cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Germline mutations in BRCA1 and BRCA2 predispose to pancreatic cancer. We estimated the incidence of pancreatic cancer in a cohort of female carriers of BRCA1 and BRCA2 mutation. We also estimated survival rates in pancreatic cancer cases from families with a BRCA mutation. METHODS: We followed 5149 women with a mutation for new cases of pancreatic cancer. The standardised incidence ratios (SIR) for pancreatic cancer were calculated based on age group and country of residence. We also reviewed the pedigrees of 8140 pedigrees with a BRCA1 or a BRCA2 mutation for those with a case of pancreatic cancer. We recorded the year of diagnosis and the year of death for 351 identified cases. RESULTS: Eight incident pancreatic cancer cases were identified among all mutation carriers. The SIR for BRCA1 carriers was 2.55 (95% CI=1.03-5.31, P=0.04) and for BRCA2 carriers was 2.13 (95% CI=0.36-7.03, P=0.3). The 5-year survival rate was 5% for cases from a BRCA1 family and 4% for cases from a BRCA2 family. CONCLUSION: The risk of pancreatic cancer is approximately doubled in female BRCA carriers. The poor survival in familial pancreatic cancer underscores the need for novel anti-tumoural strategies.

The prognostic significance of the metastatic lymph node ratio in Dukes stage C colorectal cancer in a district general hospital.

AIM: Our aim was to determine if the lymph node ratio would predict overall survival and disease-free survival in Dukes C colorectal cancer in a district general hospital setting in the UK. METHOD: Fifty-six patients were analysed from a prospectively maintained colorectal cancer database. The lymph node ratio was defined as the number of positive lymph nodes divided by the total number of nodes harvested. Comparison was made between the lymph node ratio,TNM nodal status and number of positive lymph nodes by the Kaplan-Meier method. An analysis of covariates was performed by a Cox proportional hazard regression analysis. RESULTS: A lymph node ratio of > 0.25 is prognostically significant for overall survival (P = 0.03) and disease-free survival (P = 0.0003). The lymph node ratio was the strongest covariate in the multivariate regression analysis for recurrence (P = 0.003). CONCLUSION: The lymph node ratio may help clinicians determine which patients have a more aggressive tumour biology and direct appropriate more aggressive chemotherapy regimes towards these patients.

Does family history predict the age at onset of new breast cancers in BRCA1 and BRCA2 mutation-positive families?

Women who carry BRCA mutations are advised to begin breast cancer screening based on the age-specific risks of breast cancer development. It is not clear to what extent the family history of breast cancer influences age of onset. We evaluated the use of family history to predict the age of breast cancer onset in BRCA mutation carriers. Pedigrees from an Ontario-based registry were reviewed to identify the index case of breast cancer (most recent diagnosis) and other family cases of breast cancer. The youngest age of breast cancer diagnosis and mean age at breast cancer diagnosis in the other family cases were compared to the age of onset in the index case. The 260 BRCA1 and 213 BRCA2 pedigrees were reviewed. In BRCA2 families, the index case was diagnosed on average at 44.4 years when the youngest reported family case was less than or equal to 35 years, compared to 51.9 years when the earliest cases were diagnosed after age 50 (p = 0.04). A modest trend was seen for BRCA1 carriers, but this was not statistically significant. To a small extent, the onset of breast cancer in a BRCA2 mutation carrier can be predicted from her family history of cancer, however, the trend is modest and should not alter clinical recommendations regarding initiation of screening.

Family history as a predictor of uptake of cancer preventive procedures by women with a BRCA1 or BRCA2 mutation.

Women with a BRCA1 or BRCA2 mutation are at an elevated risk of developing breast and ovarian cancer; however, it is unclear to what extent family history influences the uptake of cancer prevention options. Women with a BRCA1/2 mutation completed a follow-up questionnaire that assessed uptake of cancer preventive options. The pedigree of each woman was reviewed, and information was recorded on cancers diagnosed in relatives. Five hundred and seventeen women were included in the study. Women with a sister with breast cancer were more likely to have a prophylactic mastectomy than those without a sister with breast cancer [odds ratios (OR) = 2.4, p = 0.003]. Uptake of prophylactic mastectomy was significantly lower in women with a mother with ovarian cancer compared with those whose mother did not have ovarian cancer (OR = 0.4, p = 0.01). Having a mother or sister with ovarian cancer significantly predicted the uptake of prophylactic oophorectomy (OR = 1.6, p = 0.04). Women with a BRCA2 mutation were less likely to have a prophylactic oophorectomy than those with a BRCA1 mutation (OR = 0.49, p = 0.0004). Among women with a BRCA1 or BRCA2 mutation, family history predicts the uptake of prophylactic mastectomy and prophylactic oophorectomy.

Prolonged survival among women with BRCA germline mutations and advanced endometrial cancer: a case series.

It is unclear if BRCA mutation carriers diagnosed with advanced endometrial cancer have a better prognosis compared to sporadic cases. From a population database of BRCA1 and 2 mutation carriers in Southwestern Ontario, Canada, we identified three women with advanced-stage endometrial cancer. They were 57, 59, and 64 years of age, and of English/Scottish, Ashkenazi Jewish, and English heritage, respectively. They had different mutations in BRCA1 (Q1240X:C3837T; 68_69delAG; 1961delA). One had a sarcomatoid carcinoma and two had uterine papillary serous carcinoma. All had stage IVB disease, with surgery followed by adjuvant chemotherapy and/or radiotherapy. Follow-up has ranged from 3.3 to 14.6 years. They are still alive and well with no evidence of recurrent disease. This observation raises the question as to whether BRCA mutations may be associated with a better prognosis in patients with advanced endometrial cancer.

CMT1X phenotypes represent loss of GJB1 gene function.

OBJECTIVE: To investigate possible genotype-phenotype correlations and to evaluate the natural history of patients with Charcot-Marie-Tooth disease type 1X (CMT1X). BACKGROUND: CMT1X is caused by over 260 distinct mutations in the gap junction beta 1 (GJB1) gene, located on the X chromosome, which encodes the gap junction protein connexin 32 (Cx32). The natural history of CMT1X is poorly understood, and it remains unknown whether particular mutations cause more severe neuropathies through abnormal gain-of-function mechanisms. METHODS: We evaluated 73 male patients with CMT1X, who each have 1 of 28 different GJB1 mutations predicted to affect nearly all domains of Cx32. Disability was evaluated quantitatively by the CMT Neuropathy Score (CMTNS) as well as by the CMT Symptom Score (CMTSS) and the CMT Examination Score (CMTES), which are both based on the CMTNS. Patients were also evaluated by neurophysiology. RESULTS: In all patients, disability increased with age, and the degree of disability was comparable with that observed in patients with a documented GJB1 deletion. Disability correlated with a loss of motor units as assessed by motor unit number estimates. CONCLUSIONS: Taken together, these data suggest that most GJB1 mutations cause neuropathy by a loss of normal connexin 32 function. Therefore, treatment of male patients with Charcot-Marie-Tooth disease type 1X may prove amenable to gene replacement strategies.

DNA repair capacity as a possible biomarker of breast cancer risk in female BRCA1 mutation carriers.

The BRCA1 gene product helps to maintain genomic integrity through its participation in the cellular response to DNA damage: specifically, the repair of double-stranded DNA breaks. An impaired cellular response to DNA damage is a plausible mechanism whereby BRCA1 mutation carriers are at increased risk of breast cancer. Hence, an individual's capacity to repair DNA may serve as a useful biomarker of breast cancer risk. The overall aim of the current study was to identify a biomarker of DNA repair capacity that could distinguish between BRCA1 mutation carriers and non-carriers. DNA repair capacity was assessed using three validated assays: the single-cell alkaline gel electrophoresis (comet) assay, the micronucleus test, and the enumeration of gamma-H2AX nuclear foci. DNA repair capacity of peripheral blood lymphocytes from 25 cancer-free female heterozygous BRCA1 mutation carriers and 25 non-carrier controls was assessed at baseline and following cell exposure to gamma-irradiation (2 Gy). We found no significant differences in the mean tail moment, in the number of micronuclei or in the number of gamma-H2AX nuclear foci between the carriers and non-carriers at baseline, and following gamma-irradiation. These data suggest that these assays are not likely to be useful in the identification of women at a high risk for breast cancer.

Clinical significance of the RT-PCR positive sentinel node in melanoma.

BACKGROUND: The clinical relevance of RT-PCR positivity for melanoma markers in the sentinel node remains controversial. Our purpose was to determine whether patients with a histologically negative but RT-PCR positive node were at an increased risk for recurrence than their RT-PCR negative counterparts. METHODS: Thirty-nine adult patients underwent sentinel node biopsies for melanoma between 1998 and 2000. Each sentinel node was bivalved. Half was serially sectioned and examined by routine hematoxylin and eosin (H&E) and immunohistochemistry (IHC; S100, HMB-45, melanA, and tyrosinase). The other half was analyzed by a nested RT-PCR assay for tyrosinase. RESULTS: Patients were followed for recurrence with a mean follow-up of 71.1 months. The odds ratio of recurrence for RT-PCR positive versus RT-PCR negative patients was 1.39 (0.34, 5.62; p = 0.73). Within the histology negative subgroups, the risk of recurrence in the RT-PCR positive group (26.7%) was not significantly different from the risk of recurrence in the RT-PCR negative group (22.2%) (p = 0.33 chi-squared). RT-PCR of the sentinel node was not a predictor for recurrence on multivariate analysis (p = 0.65). CONCLUSION: Sentinel node RT-PCR positivity did not risk stratify histologically negative melanoma patients beyond routine pathologic examination in this series.

Protein kinase C alpha expression in normal breast, ductal carcinoma in situ and invasive ductal carcinoma.

The purpose of this study was to determine if Protein Kinase C alpha (PKC alpha) is altered in expression or localisation in normal breast, ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC). We obtained 14 mixed cases of invasive ductal carcinoma (IDC) and DCIS, 36 pure DCIS cases and 25 cases of normal breast. The sections were stained immunohistochemically for PKC alpha expression. Staining was cytoplasmic. The results showed a progressive reduction in staining intensity from normal breast to invasive ductal carcinoma. The staining pattern was heterogeneous in the cytoplasm of DCIS and IDC, but homogeneous in the cytoplasm of normal breast ductal epithelium. Interestingly, mitotic cells and cells with aberrant nuclear morphology showed increased cytoplasmic staining in DCIS and IDC. PKC alpha activity is altered in dividing or abnormal cells, but overall expression is reduced in IDC. This raises the possibility of an alteration in the subcellular localisation of PKC alpha which may relate to changes in desmosomal adhesive state.

Family cancer histories predictive of a high risk of hereditary non-polyposis colorectal cancer associate significantly with a genomic rearrangement in hMSH2 or hMLH1.

Hereditary non-polyposis colorectal cancer (HNPCC) results from inactivating germline mutations in a set of DNA-mismatch-repair genes, of which the most clinically relevant are hMSH2 and hMLH1. Computer-assisted pedigree risk assessment tools are available to assist in the calculation of an individual's likelihood of bearing such a deleterious mutation. One such tool, cancergene version 3.4 (http://www3.utsouthwestern.edu/cancergene) was used to assess the risk of a deleterious mutation in the genes hMSH2 and/or hMLH1 in a series of probands selected from a panel of 67 South-western Ontario kindred previously identified as likely candidates for HNPCC by established clinical criteria. A DNA sample isolated from peripheral blood leukocytes obtained from each of these probands was examined for genomic rearrangement using the multiplex ligation-dependent probe amplification (MLPA) method. Of the individuals calculated to have a risk of >50% of a hMSH2 or hMLH1 gene mutation by the CancerGene risk assessment tool, 69% (9/13) were shown to have a genomic rearrangement resulting in the deletion of one or more exons of one of these two genes. Family cancer histories predictive of a high risk of HNPCC significantly associate with a genomic rearrangement in hMSH2 or hMLH1.

Breast-feeding and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Several studies have reported that the risk of breast cancer decreases with increasing duration of breast-feeding. Whether breast-feeding is associated with a reduced risk of hereditary breast cancer in women who carry deleterious BRCA1 and BRCA2 mutations is currently unknown. METHODS: We conducted a case-control study of women with deleterious mutations in either the BRCA1 or the BRCA2 gene. Study participants, drawn from an international cohort, were matched on the basis of BRCA mutation (BRCA1 [n = 685] or BRCA2 [n = 280]), year of birth (+/-2 years), and country of residence. The study involved 965 case subjects diagnosed with breast cancer and 965 control subjects who had no history of breast or ovarian cancer. Information on pregnancies and breast-feeding practices was derived from a questionnaire administered to the women during the course of genetic counseling. Conditional logistic regression analyses were used to estimate odds ratios (ORs) for the risk of breast cancer. All statistical tests were two-sided. RESULTS: Among women with BRCA1 mutations, the mean total duration of breast-feeding was statistically significantly shorter for case subjects than for control subjects (6.0 versus 8.7 months, respectively; mean difference = 2.7 months, 95% confidence interval [CI] = 1.4 to 4.0; P<.001). The total duration of breast-feeding was associated with a reduced risk of breast cancer (for each month of breast-feeding, OR = 0.98, 95% CI = 0.97 to 0.99; P(trend)<.001). Women with BRCA1 mutations who breast-fed for more than 1 year were less likely to have breast cancer than those who never breast-fed (OR = 0.55, 95% CI = 0.38 to 0.80; P =.001), although no such association was seen for BRCA2 (OR = 0.95, 95% CI = 0.56 to 1.59; P =.83). CONCLUSIONS: Women with deleterious BRCA1 mutations who breast-fed for a cumulative total of more than 1 year had a statistically significantly reduced risk of breast cancer.

Ascorbic acid loss in vegetables: adequacy of a hospital cook-chill system.

This research evaluates the ascorbic acid loss of vegetables prepared in a hospital cook-chill plated system. The ascorbic acid loss of three vegetable samples (carrots, peas and potatoes) were measured at various points in the cook-chill system and analysed using the DCPIP method. Substantial losses for all vegetables were identified at the cooking and regeneration stages. The ascorbic acid levels of the selected vegetables when raw ranged from 6 to 10 mg/100 g sample. At the end of the food service cycle the ascorbic acid content of the vegetables was reduced to 1.7-5.8 mg/100 g sample. The largest percentage loss of ascorbic acid, i.e. 76%, was found in mashed potatoes. Peas incurred the least percentage loss, i.e. 42%. This progressive deterioration during the cook-chill plated catering system causes an insubstantial presence of ascorbic acid in the food served to hospitalised patients.

Pathological findings in the x-linked form of Charcot-Marie-Tooth disease: a morphometric and ultrastructural analysis.

Mutations in the connexin 32 gene (Cx 32) are associated with the x-linked form of Charcot-Marie-Tooth disease (CMTX) and segregate with a CMT 1 phenotype. The gap junction protein Cx 32 is expressed in myelinating Schwann cells and has been localized to regions of non-compacted cytoplasm in paranodes and in Schmidt-Lanterman incisures. Mutant Cx 32 myelin proteins are predicted to impair Schwann cell functions. We have studied the resulting pathology in motor and sensory nerves from the probands of 13 CMTX kindreds with precisely defined genotype. This report provides a detailed descriptive and morphometric analysis of 14 CMTX nerve biopsy samples, taken at various stages in the development of the neuropathy and studied by light and electron microscopic examination. Findings indicated unusually prominent changes in paranodal myelin with resulting widened nodes of Ranvier, but with segmental demyelination being less common. In parallel early axonal cytoskeletal abnormalities were noted, which were followed later by axonal atrophy, degeneration and loss of myelinated nerve fibers, occurring in a length-dependent fashion. Regenerative sprouting was also unusually prominent. Ultrastructural abnormalities included a frequent dilatation of the adaxonal spaces, prominence of the adaxonal Schwann cell cytoplasm and widening of the Schmidt-Lanterman incisures. We conclude that mutations in Cx 32 gap junction protein lead to a compromise of Schwann cell functions and to impaired Schwann cell-axon interactions with subsequent pathology in both myelin and axons.

Allele-specific non-CpG methylation of the Nf1 gene during early mouse development.

Recent reports of cytosine methylation occurring at CpA and CpT dinucleotides in murine ES cells as well as in Drosophila have renewed interest in methylation at sites other than CpGs. Our examination of the murine neurofibromatosis type 1 gene by sodium bisulfite genomic sequencing has revealed non-CpG methylation primarily in the oocyte and the maternally derived allele of the 2-cell embryo, with markedly lower levels found in sperm. Non-CpG methylation was not found in later stages of embryo development or in adult tissue. Our results suggest that maternal-specific de novo non-CpG methylation has occurred sometime between ovulation and formation of the 2-cell embryo, while during the same period the paternally derived allele has undergone site-specific active demethylation. Our data demonstrate both stage and parent-of-origin specific changes in methylation patterns within the neurofibromatosis type 1 coding region-involving cytosines located at both CpG and non-CpG dinucleotides.

Variable expressivity of familial medullary thyroid carcinoma (FMTC) due to a RET V804M (GTG-->ATG) mutation.

BACKGROUND: Multiple endocrine neoplasia type 2 (MEN 2) and familial medullary thyroid carcinoma (FMTC) are autosomal dominantly inherited cancer syndromes that predispose to C-cell hyperplasia and MTC. MEN 2A and FMTC are caused by mutations in the RET proto-oncogene. METHODS: We used a multiplex polymerase chain reaction-based assay to screen exons 10, 11, 13, and 14 of RET for mutations in 2 families with FMTC. We correlated mutation status with calcitonin and pathologic studies to determine genotype-phenotype correlations. RESULTS: We identified a mutation in codon 804 in exon 14 (GTG-->ATG; V804M) in both families. An 86-year-old person who was a gene carrier and other individuals over age 70 who were suspected by pedigree analysis to be gene carriers had no overt clinical evidence of MTC. Four of 21 patients who underwent a thyroidectomy also had papillary thyroid cancer. One individual in each family had metastatic MTC at age 30 and 32 years, and all 26 people having thyroidectomies had either MTC or C-cell hyperplasia, leading us to continue to recommend prophylactic thyroidectomy for all identified patients who were gene carriers. CONCLUSIONS: Because of active MTC in younger members of these families, including metastases, we have continued to advocate thyroid surgery in mutation-positive individuals. While DNA diagnosis of gene carriers and subsequent genetic counseling was relatively straightforward, the acceptance of surgical recommendations was more difficult for some individuals. These families demonstrate that the search for RET mutations should include exons 13, 14, 15, and 16 in patients whose studies in exons 10 and 11 are negative.